Snort is an open source network intrusion detection and prevention system (NIDS/NIPS).

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1answer
168 views

Documentation on Snort rules and alert tuning, especially for new users

I just started using Snort. There is a lot to it. I'm just looking for better documentation of what some of the Snort rules actually mean -- i.e. How I should react to them when I have an alert for a ...
0
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1answer
380 views

Question on SNORT Rule

I am new to SNORT and can not figure out what the following rule means: alert tcp $EXTERNAL_NET any-> $HOME_NET any (msg:"SCAN FIN"; flags: F; reference:arachnids,27;
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1answer
39 views

Suricata Signature Explanation

I am trying to figure out some Suricata(or Snort) signatures, more specifically, what they mean, what they prevent and have some problems about meanings of keywords. I will not write irrelevant parts. ...
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0answers
26 views

Snort rules fo detecting meterpreter sessions

I am learning configuring snort in my setup consisting of an attacker(linux), a victim(android smartphone) and 1 detection system. So far, i have been able to log all the packets between the attacker ...
2
votes
1answer
103 views

Problem with Snort rule

alert tcp $HOME_NET any -> $EXTERNAL_NET 80 (msg:"Get2 method"; flow: to_server, established; dsize: >20; sid:1000006; priority: 15) Snort does not generate any alert, whereas when I write the ...
3
votes
1answer
95 views

How use snort with local.rules in offline mode?

I'm using SecurityOnion distro and I would to run snort on my pcap files. Is there a way to specify just one rule? I couldn't understand whether local.rules is used. How can I show only the result ...
0
votes
1answer
13 views

Questions on snort generating too many events and not sending to syslog

New to snort here. I downloaded snort (2.9.6.0 GRE Build 47) on my Ubuntu 14.04, also downloaded emergingthreat rules. I ran the following command root@myhp:~/pkgs/emergeThreats/snortRules# snort -...
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0answers
36 views

Frequency of Stealth scan?

Background I am working on snort Portscan Module to detect Stealth scans.Snort uses good amount of datastructures to capture scanning events and to explicitly set the threshold values. typedef ...
9
votes
4answers
42k views

Testing Snort IDS installation

What is the easiest way to test Snort IDS after installing? Would using and writing a rule that captures all of the traffic work? alert ip any any -> any any ( msg: "ICMP packet detected!"; sid: ...
0
votes
1answer
101 views

fwsnort - How safe compared with Snort/Suricata?

How safe is 'fwsnort' compared to a real Snort / Suricata instance? What's the percentage of VRT / ET Rules, that fwsnort can actually use? I read somewhere from an older article its only ~ 60% - is ...
4
votes
1answer
1k views

Snort even though working properly does not report majority of rules

I have installed Snort 2.9.7.0 and it does not detect majority of attacks, such as nmap port scans, downloading exe files, opening documents containing keyword "root". I use Snort together with ...
1
vote
1answer
2k views

Block Packets in snort

In rules configuration of snort I have: alert tcp any any -> any any (msg:"HTTP Connection"; react:block;) However when I add: alert icmp any any -> any any (msg:"HTTP Connection"; react:...
2
votes
1answer
3k views

Snort & Logging

I am looking for some support on using Snort in Windows 7. My experience so far is using WireShark, so this is new territory to me. I would like to use Snort to perform a trace, which, after it ends,...
0
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0answers
47 views

is it normal that the alert file of snort is empty?

I installed snort on an ubuntu machine, then I created a simple rule to alert on ICMP packets. I started snort: snort -c /etc/snort/snort.conf -A console -l /var/log/snort and I sent a ping from ...
1
vote
0answers
14 views

Snort Modules Tweaking

I want to tweak and add new functionalities to snort code(Preprocessor)(v2.9.8). So,i have installed snort using source code,on ubuntu 14.04,however due to unknown problems,functionalities aren't ...
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0answers
41 views

Snort false positive, yet suspicious

I have Snort installed and tuned nicely with ET Rules on my pfSense, both my pfSense and the modem are using Googles public DNS 8.8.8.8. Recently I was denied access to google.com, and by reviewing ...
0
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0answers
29 views

Detecting Spamming activities of Botnets

Remarks Hello Everyone,thanks for being a nice platform for expressing Everyone's Doubts/Views. Problem Statement I want to detect spamming activity of botnets Background Information about ...
2
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0answers
69 views

Snort Portscan Preprocessor Analysis

Remarks I really apologize if this content isn't matching the community, but I am not getting approved on snort-mailing lists and I don't know what can I do for the same, therefore I feel this can be ...
1
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2answers
9k views

How to connect sensors such as Snort to AlienVault SIEM?

I want to connect some sensors such as Snort and OSSEC to AlienVault SIEM. How can i do that?! Is it possible to send logs via syslog?
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2answers
32 views

Snort Unable to detect portscans in LAN

Setup Information I am doing experiment on portscan detection using snort 2.9.8.I have 10 systems in my lab with id:1,2,3,...,10. i have installed snort in my lab-pc with id:1.Now i am using Pc with ...
4
votes
1answer
149 views

How do I use a directory of YARA files?

I'm going through the Malware Cookbook PEScanner and they want a path to my YARA files to search on. I currently have a directory full of YARA rules for known pieces of malware. What would be the ...
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0answers
11 views

snort spp_sfPortscan Preprocessor Customization [closed]

I am working in snort 2.9.8.0. I want to modify the snort code for Portscanning Detection,i.e spp_sfPortscan.c and its related code to build a customized portScan detector. Ex:suppose A is scanning ...
1
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2answers
475 views

Snort “Protocol mismatch” from SSH preprocessor

TL;DR -- What does "protocol mismatch" even mean, and how is this a threat? Can I just suppress it? We are busy tuning Snort. The SSH preprocessor section looks like this, which comes directly from ...
0
votes
1answer
209 views

(spp_sdf) SDF Combination Alerts in Snort

I'm testing Snort in IDS mode and have been receiving a few (spp_sdf) SDF Combination Alerts as below. Seems like it happens when I visit certain but not all https sites. Tried to google this alert ...
1
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1answer
95 views

Are snort rules applied per packet or per flow

I would like to understand if snort rules are applied for each packet in a flow between a source and destination separately? For instance, when packet 1 of the flow arrives at the IDS, all the rules ...
0
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1answer
89 views

snort rule to detect relay attempt not working

I am trying to detect a relay attempt on smtp server, but nothing gets logs when I test it out. The snort rule to detect a relay attempt which I tried using is: alert tcp $SMTP_SERVERS 25 -> ...
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0answers
27 views

Snort matching against single packets

For a specific task, I'd like to match snort rules against the first 1-2 packets of each flow in the network without waiting for the other subsequent flow packets. Can I do this with snort? If so, how?...
0
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0answers
168 views

Suricata IPS manual blocking/unblocking vs. snort and guardian

Does anyone have experience with using Suricata as an IPS? Im on Debian and I'd like to be able to manually block and unblock specific ip addresses (iptables). I've not used Suricata as I am currently ...
0
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1answer
70 views

What does this snort rule mean?

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"MALWARE-BACKDOOR access remote pc runtime detection - init connection"; flow:to_server,established; content:"|99 F3 00 00 00 00 00 00 FF FF FF FF|"...
3
votes
1answer
75 views

How to make Snort not log sensitive data from the sniffed traffic?

I have Snort in my network which I use for IDS and it is residing on a VM that receives all mirrored traffic from the switch. I am having a web applications that users use and they login, operate on ...
0
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0answers
117 views

Snort arpspoof preprocessor not giving alerts

I'm attempting to use Snort to detect a simple arpspoof attack on a test network I've set up. I have the following 4 ip addresses on this network. 192.168.1.1 Router 00:18:39:EC:F5:78 192.168.1.2 ...
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0answers
75 views

Snort rule to detect More Fragments fragbit not working

I have a Virtualbox setup with Snort running on a Windows 7 host and Kali Linux as the attacking machine, connected on an internal network. I'm investigating ways to get Snort to detect fragmentation ...
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0answers
46 views

Snort signatures not working [closed]

I am using snort to detect signature for IDS but some rule not detected by snort which is highlighted below. Kindly, sort this out, I'm stuck here.
0
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0answers
118 views

Switching from Snort rules to Emerging Threats. Is there a way to know which ET rule sid covers the same vulnerabilty as Snort rule sid?

Our company has been using the snort community rules and we have tuned our rule files over years to our specific needs. Now our company has decided to use Emerging Threats (ET) open rules. The ET ...
1
vote
1answer
93 views

Understanding Snort log

I am new to Snort, and I have ran Snort through a .cap file and got the logs that I should interpret. If I take for instance a block of log like the one below: [**] [1:2463:7] EXPLOIT IGMP IGAP ...
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0answers
11 views

Adding Windows 7 VM as a log source/forcing the IDS inline

I'm investigating ways to add my Windows 7 VM as a log source or even run that traffic through my IDS VM and then out to the internet but I'm not entirely sure how to approach it. Does anybody have ...
1
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0answers
16 views

get session data (stream data) into Snort ids [closed]

Can any one point to me where (in the code) Snort are stored just before they send to httprespect or got written to the output files? Thanks.
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0answers
201 views

Snort gives “could not create the registry key” error for multiple kinds of operations

I've set up a host-only network in Virtualbox consisting of a Kali linux machine and a Windows 7 machine (the host is running OS X). I have Snort installed on Windows 7 and am attempting to verify ...
-1
votes
1answer
366 views

snort rule explanation

I'm quite new to Snort, Could anyone explain these two rules? Specifically, why do they contain more than one "content" field ? alert tcp $EXTERNAL_NET any -> $HOME_NET any ( msg:"ET TROJAN Reply ...
1
vote
1answer
132 views

SNORT sfportscan alert format [closed]

How can I modify the output alert from sfportscan ? Ex : output alert_csv: /var/log/snort/portscan.log timestamp,src,dst,dstport,msg OBS: I can set output for default alert file with this method ?
19
votes
5answers
3k views

DoS in local network computer

I'm using Snort to study detection, and I wanted to simulate a DoS attack from the inside to another computer in my home network, but I have a question. If I start to flood the target computer with ...
5
votes
2answers
269 views

Ideas on how I can fragment captured network traffic?

I am trying to create a lab environment where I can analyze common IDS solutions (starting with Snort specifically) and their ability to reassemble fragmented IP trains. I have a collection of ...
0
votes
1answer
70 views

Windows SQL Server Intrusion Detection [closed]

I'm looking into Snort to carry our basic intrusion detection, but finding it hard going. What other Intrusion Detection software is there that is good to use for SQL Server?
1
vote
1answer
317 views

What does the http_uri content modifier do is SNORT

I am very confused about exactly what http_uri does. Can someone explain this to me w.r.t NORMALIZED and UNNORMALIZED uri fields?
0
votes
2answers
522 views

How to make sense of, and act on, Snort Rules?

I am a relatively new Snort user with years of sys admin experience. I feel that I must be missing something, because I find Snort rules to be completely undocumented and incomprehensible. Because of ...
0
votes
1answer
231 views

Snort - Rule: Alert all php requests

I am trying to understand writing rules for snort. Further goal is detection of sql injections like here. I've read the documentation of snort rules and created this rule: alert tcp any any -> ...
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0answers
112 views

Snort rule does not work when combining “content” fields

I'm trying to write a snort rule which outputs an alert whenever a web server returns an HTML document containing a specific string. I've come up with the following rule: alert tcp any any -> any ...
3
votes
1answer
407 views

How to detect changing IP address and user agent on a HTTP session?

I have some HTTP logs where I see the hacker changing his IP every request, and occasionally changing his useragent. Is there a way to detect this automatically? Perhaps a snort rule? or any other ...
0
votes
1answer
326 views

Snort: Arpspoof preprocessor events not showing up in BASE UI

I have followed this guide to install Snort, using Barnyard2, BASE, IIS, and MySql. My Snort is up & running and loads of events are being logged. After weeding out some false positives, I wanted ...
1
vote
0answers
271 views

Snort alerts analysis (web interface) [closed]

I have a question about Snort (or maybe any other IDS/IPS, any working solutions would be ok). The goal is to set up some web interface providing a way to view the whole TCP stream packets of each ...